1. Field of the Invention
The present invention relates generally to ice making machines, and more particularly to a water supply system for ice making machines including a reversible circulating pump.
2. Description of the Prior Art
Heretofore, there have been proposed various water supply systems to be used in association with an ice making machine, as will be seen in FIGS. 14 to 16 of the accompanying drawings. In the water supply system shown in FIG. 14, there are installed, above an ice forming member 1 equipped with a cooling or evaporator pipe 1a, an ice forming water distribution pipe 2 and a deicing or defreezing water distribution pipe 3 which are in fluid communication with a water tank 4 through first and second circulating pumps 5 and 5a, respectively. Upon operation of the circulating pump 5, water (referred to as ice forming water) is supplied onto a freezing surface of the ice forming member 1 to cause an ice slab 1b to be formed and grow thereon. On the other hand, when the circulating pump 5a is operated, deicing or defreezing water is distributed over a rear surface of the ice forming member 1 to defreeze the ice slab 1b for removal thereof from the ice forming member. Reference character 4a denotes a water supply pipe connected to an external water service system (not shown) for supplying water to the water tank 4.
In the case of the water supply system shown in FIG. 15, the ice forming water distribution pipe 2 and the defreezing water distribution pipe 3 are connected to pipes incorporating first and second solenoid valves 7 and 7a, respectively. By energizing and deenergizing selectively the first and second solenoid valves 7 and 7a, ice forming or defreezing water can be supplied in a manner similar to that described in conjunction with FIG. 14.
FIG. 16 shows another known water supply system in which the ice forming water distribution pipe 2 and the deicing or defreezing water distribution pipe 3 are connected to a conventional three-way valve 7 so that ice forming water or defreezing water can be selectively fed to the ice forming member 1.
Although all the prior art water supply systems described above are so designed that the defreezing water is supplied from the water tank 4, there have also been known such water supply systems in which defreezing water is tapped from a separate water supply source or an external water supply system such as a city water supply service system.
The hitherto known ice making machines provided with water supply systems having arrangements such as shown in FIGS. 14 to 16 suffer from various and numerous shortcomings such as described below:
(1) First, in the case of the arrangement shown in FIG. 14, not only are two circulating pumps required but a control apparatus for controlling the operation of the pumps is required, thus involving high expenditure, as well as a relatively greater likelihood of failure and poor reliability in operation.
(2) Although the system shown in FIG. 15 can operate with the single circulating pump, two solenoid valves are required. Thus, this system suffers from disadvantages similar to those mentioned above.
(3) In the system shown in FIG. 16, the combination of one circulating pump with one solenoid valve is sufficient for realizing the intended operation cycle. However, the solenoid valve is constituted by a three-way valve. This makes it difficult to provide an inexpensive system while still assuring high reliability.
(4) Further, a problem existing in common with all water supply systems known heretofore is that a relatively large number of parts are required, whereby the space occupied by the system is necessarily increased, thus making it difficult to produce small-sized ice making machines.